Magnetic material and coil component using same

Abstract

A magnetic material contains multiple metal grains constituted by soft magnetic alloy and oxide film formed on a surface of the metal grains, which soft magnetic alloy includes Fe and a metal element that oxidizes more easily than Fe, wherein the magnetic material forms a grain compact having first bonding parts where adjacent metal grains are contacted and directly bonded together, second bonding parts where adjacent metal grains are bonded together via the oxide film formed around the entire surface of said adjacent metal grains other than the first bonding parts, and voids formed in an area other than the first and second bonding parts and surrounded by the oxide film.

We claim: 
     
       1. A magnetic material containing multiple metal grains constituted by soft magnetic alloy and oxide film formed on a surface of the metal grains, wherein the soft magnetic alloy and the oxide film include Fe and a metal element that oxidizes more easily than Fe, wherein
 the magnetic material forms a grain compact having first bonding parts where adjacent metal grains are contacted and directly bonded together by alloy-to-alloy bonding in areas where no oxide film exists, second bonding parts where adjacent metal grains are bonded together by the oxide film formed around the entire surface of said adjacent metal grains other than the first bonding parts, and voids formed in an area other than the first and second bonding parts and surrounded by the oxide film, said alloy-to-alloy bonding including metal bonds where regularity of atomic arrangement is satisfied. 
 
     
     
       2. A magnetic material according to  claim 1 , wherein the soft magnetic alloy contains Si in an amount of 0.5 to 7.0 percent by weight. 
     
     
       3. A magnetic material according to  claim 1 , wherein the oxide film formed on the surface of the metal grains contains Cr or Al. 
     
     
       4. A magnetic material according to  claim 1 , wherein the average grain size of the metal grains is 2 to 30 μm. 
     
     
       5. A magnetic material according to  claim 1 , wherein the grain compact has a magnetic permeability of 33 to 54. 
     
     
       6. A magnetic material according to  claim 2 , wherein the grain compact has a magnetic permeability of 33 to 54. 
     
     
       7. A magnetic material according to  claim 3 , wherein the grain compact has a magnetic permeability of 33 to 54. 
     
     
       8. A magnetic material according to  claim 4 , wherein the grain compact has a magnetic permeability of 33 to 54. 
     
     
       9. The magnetic material according to  claim 1 , wherein the grains are bonded together only by the first bonding parts and the second bonding parts. 
     
     
       10. The magnetic material according to  claim 1 , wherein the grain compact is a sintered compact.